Personal cellular zone with signal resolution

ABSTRACT

A method and apparatus for providing a cellular zone is disclosed. A communication link connects a cellular base station and a wireless access point. A typical communication link can be a wire-based communication network, such as the Internet, using IP telephony protocol. The wireless access point communicates with a cell phone over a cellular frequency and thereby establishes the cellular zone. Where the area of the cellular zone and the coverage area of the cellular base station overlap, continuous arbitration is performed to select a communications channel. The strength of a first signal received from the cellular base station is compared to the strength of a second signal received from the wireless access point. Selection criteria include signal strength and a time-oriented criteria to maintain continuity of communication channel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of cellular communications.In particular, the present invention provides a method and apparatus forintegrating a cellular zone into a cellular communications network.

2. Description of the Related Art

Currently, cellular networks provide cellular telephone service to widegeographical areas. A cellular network generally comprises a set ofoverlapping cells, a cell being a geographical area within radio contactof a fixed transmitter, normally known as a base station. Base stationsconsist of transceivers which send and receive signals to other basestations within a given frequency range as well as to any distributedtransceivers (often a cellular phone) with the cell. Cells are positionsso as to overlap with each other, thereby providing radio coverage overa greater area than the area of any one cell. Radio communicationbetween base stations is facilitated by placing one base station withinthe coverage area of another base station. A handing-off protocolenables propagation of a signal from one base station to another and, byextension, throughout the network. Cellular networks are inherentlyasymmetric with a set of fixed main transceivers each serving a cell anda set of distributed transceivers which provide services to thenetwork's users.

The primary requirement for operation of a cellular network is a way forthe distributed transceivers to distinguish between a signal from itsown transmitter and a signal from other transmitters. Two commonsolutions to this are frequency division multiple access (FDMA) and codedivision multiple access (CDMA). FDMA works by assigning a differentoperational frequency for each neighbouring cell. By tuning to thefrequency of a chosen cell the distributed stations can avoid the signalfrom other neighbours. CDMA is a form of multiplexing, which enablesnumerous signals to occupy a single transmission channel, optimizing theuse of available bandwidth. The technology is used inultra-high-frequency (UHF) cellular telephone systems in the 800-MHz and1.9-GHz bands. CDMA uses spread spectrum by multiple transmitters tosend to the same receiver on the same frequency channel at the same timewithout harmful interference. In spread spectrum technology, thefrequency of the transmitted signal is made to vary according to adefined pattern (code), so it can be intercepted only by a receiverwhose frequency response is programmed with the same code, so it followsexactly along with the transmitter frequency. The CDMA channel isnominally 1.23 MHz wide.

Cellular coverage is typically provided by GSM/CDMA (Global System forMobile telecommunications/Code Division Multiple Access). GSM is aglobally accepted standard for digital cellular communication. In GSM,both signaling and speech channels are digital, which means that it isseen as a second-generation (2G) mobile phone system. GSM systemsprovide higher digital voice quality and low cost alternatives to makingcalls, such as text messaging.

New developments are emerging in which a dual mode mobile phone usingboth 802.11 and GSM/CDMA reside on the same handset. EEE 802.11, orWi-Fi, denotes a set of Wireless LAN standards developed by WorkingGroup 11 of the IEEE LAN/MAN Standards Committee (IEEE 802). The term isalso used to refer to the original 802.11, which is now sometimes called“802.11 legacy.” The 802.11 family currently includes six over-the-airmodulation techniques that all use the same protocol, the most popular(and prolific) techniques are those defined by the a, b, and gamendments to the original standard. 802.11b and 802.11g standards usethe unlicensed 2.4 gigahertz (GHz) band. The 802.11a standard uses the 5GHz band. Operating in an unregulated frequency band, 802.11b and802.11g equipment can incur interference from microwave ovens, cordlessphones, and other appliances using the same 2.4 GHz band. However, usingthe existing wireless protocols of the cellular carrier enablesoperating with existing handsets with no modification required.

If the distributed transceivers are mobile and moving from cell to cell,they have to change radio contact from cell to cell. The mechanism forthis transfer depends on the type of network and the circumstances ofthe change. For example, if there is an ongoing continuouscommunication, then transfer should be made to occur withoutinterruption. In this case, there must be clear coordination between thebase station and the mobile station. Typically such systems use somekind of multiple access independently in each cell, so an early stage ofsuch a handover is to reserve a new channel for the mobile station onthe new base station which will serve it. The mobile then moves from thechannel on its current base station to the new channel and from thatpoint on communication takes place.

With new technologies, there is a need for methods of arbitratingsignals between carrier systems. Additionally, as the “wired” and“wireless” worlds of communication come together, and as different typesof wireless technologies merge, the issue of carrier signal arbitrationand selection becomes increasingly important. New methods will addressissues relating to signal platforms. Users typically demand increasedsignal strength and signal quality. Thus, these new methods shouldprovide improved signal quality.

Although cellular network cover wide areas, there remain geographicareas that are still uncovered, for various reasons. Some of these areashave a small population base (customer base), making it not financiallyviable to install a cell tower (base station) to provide coverage inthose areas. Other areas are too remote to justify installation. Inother areas, obstructions such as mountains, hills, trees, etc. degradeperformance. In addition, man-made forms of interference, such as powerlines, degrade the signal. All of these factors may lead to extremelypoor signal quality to no signal in a given area. In the past,commercial organizations have installed special cellular antennas incommercial areas, such as malls, where a cellular user might have aproblem accessing a carrier signal through thick concrete and metal.However, there is an ongoing need to provide financially viable cellularcoverage in areas that do not have adequate carrier coverage and toarbitrate between signal carriers so as to provide signal coverage.

SUMMARY OF THE INVENTION

The present invention discloses a method and apparatus for providing acellular zone. A communication link is provided between a cellular basestation and a wireless access point. A cellular base station generallyrefers to a transceiver tower that is part of a cellular communicationnetwork. A wireless access point could be, for example, a Wireless(802.11)/Router with enhanced GSM/CDMA wireless capabilities.Alternately, the wireless access point could be a box providing GSM/CDMAand Ethernet capabilities. The wireless access point communicates with acell phone using GSM/CDMA, but can optionally use 802.11 forcommunication. The communication link from the cellular base station tothe cellular zone can be, for example, a wire-based communicationnetwork, such as the Internet. In one embodiment of the invention, thewire-based communication network is capable of transmitting signalsusing IP telephony. Cellular communication is provided between thewireless access point and a cellular telephony device to establish thecellular zone.

In one embodiment of the invention, the cellular zone and the coveragearea of a nearby cellular base station are non-overlapping. In analternative embodiment, the cellular zone and the coverage area of thecellular base station overlap in part. In the alternative embodimentwith overlapping areas, a method is provided for arbitrating between afirst signal received from the cellular base station and a second signalreceived from the wireless access point compares strengths of the firstand second signals and selects between the first and second signal basedon signal strength. The method of arbitrating further comprises atime-oriented criteria for signal selection to prevent excessiveflipping between channels in cases where signal strengths are comparableor quickly fluctuating.

Examples of certain features of the invention have been summarized hererather broadly in order that the detailed description thereof thatfollows may be better understood and in order that the contributionsthey represent to the art may be appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject of the claims appended hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

For detailed understanding of the present invention, references shouldbe made to the following detailed description of an exemplaryembodiment, taken in conjunction with the accompanying drawings, inwhich like elements have been given like numerals.

FIG. 1 illustrates a configuration in which a cellular signal isincapable of reaching an intended destination;

FIG. 2 illustrates an exemplary embodiment of the present invention;

FIG. 3 illustrates an exemplary integrated unit enabling GSM (GlobalSystem for Mobile Telecommunications);

FIG. 4 illustrates a configuration in which degraded cellular receptionoccurs;

FIG. 5 illustrates an alternative embodiment of the present invention inwhich a cellular zone is located at the periphery of a cell zone; and

FIG. 6 illustrates a flowchart for arbitrating between signals receivedfrom a base station and from a wireless access device.

DETAILED DESCRIPTION OF THE INVENTION

In view of the above, the present invention through one or more of itsvarious aspects and/or embodiments is presented to provide one or moreadvantages, such as those noted below.

FIG. 1 illustrates a configuration 100 in which a cellular signal isincapable of reaching its intended destination. The base stationgenerally comprises a transceiver tower used for the propagation anddirection of signals over the cell 115 a linked cellular network. Basestation 110 provides a maximum radius of coverage 120 to cell 115.Customer 130 happens to be located outside of the cell 115. Because ofthis, the cell phone 140 in his possession displays no signal strengthand the user cannot initiate or receive a cellular call.

FIG. 2 illustrates an exemplary embodiment 200 of the present invention.A cellular zone 238 is provided by establishing a communication channelin the cellular frequency range between a cell phone 236 and a wirelessaccess point 230. The wireless access point 230 provides cellularcoverage over a maximum radius of coverage 234. The wireless accesspoint 230 communicates with cell phone 236 using GSM/CDMA wirelesscapabilities. In an exemplary embodiment, wireless access point 230comprises an integrated Wireless (802.11)/Router with enhanced GSM/CDMAwireless capabilities. In an alternative embodiment, the wireless accesspoint comprises a box that only provides GSM/CDMA and Ethernetcapabilities and which plugs into an existing consumer WirelessAP/Router. FIG. 3 illustrates an exemplary GSM integrated unit 300.

A broadband connection 225, such as an Internet connection, connects thewireless access point 230 to an Internet Service Provider (ISP), whichin turn connects to a cellular service provider 210. A typical broadbandconnection 225 could be provided using a DSL Broadband service. Tointegrate the wireless access point 230 with the cellular network, thecustomer purchases a cellular-ready device 236 and typically activatesthe cellular zone at their home through a registration process.Registration enables the carrier 210 to know to route calls through tothe cellular zone. The wireless access point 230 registers over IPnetwork (Internet) 220 to the cellular service provider 210. Thecellular provider adds this wireless access point to its networkcoverage database and routes wireless calls to and from this location.The cellular carrier detects the entry of the cell phone 236 into thecellular zone 238 and routes phone calls appropriately. The connectionfrom the cellular carrier 210 to the consumer's cell zone 238 istypically provided via IP telephony.

The cellular carrier 210 converts voice traffic from the base station110 to an Internet Protocol (IP) telephony (i.e., Voice over InternetProtocol) and transmits the signal to the wireless access device 230 viaISP 220 and broadband connection 225. The wireless access point 230converts the IP telephony signal of the cellular service provider 210back to GSM/CDMA for transmission over cell zone 238. The cell zone 238thus is an integrated part of the cellular provider's network, and theconsumer's cellular phone 236 rings in the event of a cellular callbeing received at the wireless access point 230.

FIG. 4 illustrates one possible situation 400 in which degraded cellularreception can occur. A cellular customer 430 is located at the peripheryof a cell 115 corresponding to base station 110. Due to the customer'slocation, the GSM/CDMA phone 440 experiences reduced signal strength anddegraded quality. As a result, the user may or may not be able toinitiate or receive a cellular call. Degraded quality can also be causedby physical, geographic, or manmade limitations.

FIG. 5 illustrates an alternative embodiment 500 of the presentinvention in which a cellular zone is located at the periphery of a cellzone. Cellular zone 238 and cell 115 overlap at intersection 505.Customer 510, using his cell phone 515 within intersection 505, canreceive two signals: a first signal received from the base station(110), and a second signal received from the wireless access device(230) of the cellular zone. Resolution of the issue of zone overlap isfacilitated by registering the cellular zone with the cellularprovider's network. The GSM/CDMA wireless registration is managed by thecellular provider's network, enabling the handoff of wireless voicecommunications either from the cellular zone or the cellular network.

FIG. 6 illustrates a flowchart 600 for arbitrating between signalsreceived from a base station and from a wireless access device, as canoccur in the configuration of FIG. 5. The process of signal selection isrepeated on a periodic basis during the course of a phone call. In Box601, the strengths of the first signal from the cellular zone to thecellular phone and of the second signal from the cellular carrier'santennas are measured. These strengths are then compared to determinewhich is the stronger signal. In Box 603, the cell phone selects one ofthese signals to be used for communication based on a set of criteria.Criteria for signal selection include signal strength and atime-constraint. For example, when a stronger signal is clearlyestablished, that stronger signal will be selected. In a situation wheresignal strengths are fluctuating over a short time period, thearbitrating process maintains the communication channel that it iscurrently using for a time. This enables continuity of signal receptionand prevents constant flipping back and forth between channels. After atime in which the strength of another signal is clearly established asstronger, the stronger signal is again selected.

In an additional aspect of the present invention, the consumer can allowor disallow specific phone numbers from accessing their cell zone 238.As an example, a cell zone owner can only allow his cellular phone tooperate using the cell zone 238. One advantage of restricting useraccess is to minimize excessive calls across the consumer's privatebroadband connection. Restriction can be made by identifying specificphone numbers.

Alternatively, the consumer could limit the number of cellular phonedevices based upon the IP bandwidth in order to ensure a certain numberof concurrent connections. This information can be factored intodetermining whether a cellular phone operating within a cellular zoneleverages the carrier's network or the cellular zone.

Although the invention has been described with reference to severalexemplary embodiments, it is understood that the words that have beenused are words of description and illustration, rather than words oflimitation. Changes may be made within the purview of the appendedclaims, as presently stated and as amended, without departing from thescope and spirit of the invention in its aspects. Although the inventionhas been described with reference to particular means, materials andembodiments, the invention is not intended to be limited to theparticulars disclosed; rather, the invention extends to all functionallyequivalent structures, methods, and uses such as are within the scope ofthe appended claims.

In accordance with various embodiments of the present invention, themethods described herein are intended for operation as software programsrunning on a computer processor. Dedicated hardware implementationsincluding, but not limited to, application specific integrated circuits,programmable logic arrays and other hardware devices can likewise beconstructed to implement the methods described herein. Furthermore,alternative software implementations including, but not limited to,distributed processing or component/object distributed processing,parallel processing, or virtual machine processing can also beconstructed to implement the methods described herein.

It should also be noted that the software implementations of the presentinvention as described herein are optionally stored on a tangiblestorage medium, such as: a magnetic medium such as a disk or tape; amagneto-optical or optical medium such as a disk; or a solid statemedium such as a memory card or other package that houses one or moreread-only (non-volatile) memories, random access memories, or otherre-writable (volatile) memories. A digital file attachment to e-mail orother self-contained information archive or set of archives isconsidered a distribution medium equivalent to a tangible storagemedium. Accordingly, the invention is considered to include a tangiblestorage medium or distribution medium, as listed herein and includingart-recognized equivalents and successor media, in which the softwareimplementations herein are stored.

Although the present specification describes components and functionsimplemented in the embodiments with reference to particular standardsand protocols, the invention is not limited to such standards andprotocols. Each of the standards for Internet and other packet switchednetwork transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) representexamples of the state of the art. Such standards are periodicallysuperseded by faster or more efficient equivalents having essentiallythe same functions. Accordingly, replacement standards and protocolshaving the same functions are considered equivalents.

1. A method for providing a cellular zone to a cellular telephonydevice, comprising: providing a first communication link between acellular base station and a wireless access point; providing a secondcellular communication link between the wireless access point and thecellular telephony device to provide the cellular zone; restrictingaccess to the wireless access point from the second cellularcommunication link to a phone number corresponding to the cellulartelephony device; arbitrating between a first signal received from thecellular base station and a second signal received from the wirelessaccess point; comparing a strength of the first signal with a strengthof the second signal; and selecting a signal from one of the setconsisting of the first signal and the second signal based on comparedsignal strength.
 2. The method of claim 1, wherein the firstcommunication link further comprises a wire-based network.
 3. The methodof claim 2, wherein an IP telephony protocol is used to transmit signalswithin the wire-based network.
 4. The method of claim 1, whereinGSM/CDMA (Global System for Mobile telecommunications/Code DivisionMultiple Access) is used to provide the second cellular communicationlink in the cellular zone.
 5. The method of claim 1, further comprising:selecting a signal based on a time-oriented criteria.
 6. The method ofclaim 1 further comprising identifying the phone number of the cellulartelephony device at the wireless access point.
 7. A computer-readablemedium containing instructions that when executed by a computer performa method for providing a cellular zone for a cellular telephony device,comprising: providing a first communication link between a cellular basestation and a wireless access point; providing a second cellularcommunication link between the wireless access point and the cellulartelephony device to provide the cellular zone; restricting access to thewireless access point from the second cellular communication link to aphone number corresponding to the cellular telephony device; arbitratingbetween a first signal received from the cellular base station and asecond signal received from the wireless access point; comparing astrength of the first signal with a strength of the second signal; andselecting a signal from one of the set consisting of the first signaland the second signal based on compared signal strength.
 8. Thecomputer-readable medium of claim 7, wherein in the method providing thefirst communication link further comprises a wire-based network.
 9. Thecomputer-readable medium of claim 8, wherein in the method an IPtelephony protocol is used to transmit signals within the wire-basednetwork.
 10. The computer-readable medium of claim 7, wherein in themethod GSM/CDMA (Global System for Mobile telecommunications/CodeDivision Multiple Access) is used to provide the second cellularcommunication link in the cellular zone.
 11. The computer-readablemedium of claim 7, the method further comprising selecting a signalbased on a time-oriented criteria.
 12. An apparatus for providing acellular zone for a wireless telephony device, comprising: acommunication device that establishes a first communication link to acellular base station-and a second wireless communication link to thewireless telephony device, wherein the second wireless communicationlink is restricted to a phone number corresponding to the wirelesstelephony device; and a processor associated with the wireless telephonydevice that is configured to arbitrate between a first signal receivedfrom the cellular base station and a second signal received from thecommunication device, compare a strength of the first signal with astrength of the second signal and select a signal from one of the setconsisting of the first signal and the second signal based on comparedsignal strength.
 13. The apparatus of claim 12, wherein the firstcommunication link further comprises a wire-based network.
 14. Theapparatus of claim 13, wherein an IP telephony protocol is used totransmit signals within the wire-based network.
 15. The apparatus ofclaim 12, wherein GSM/CDMA (Global System for Mobiletelecommunications/Code Division Multiple Access) is used to provide thesecond cellular communication link in the cellular zone.
 16. Theapparatus of claim 12, wherein the processor is further configured toselect a signal based on a time-oriented criteria.